Oct.
16, 2003 — Temperatures in Alaska, the far West, Southwest and Southern
Plains are expected to be above normal for the 2003-04 winter. For other
parts of the nation, the winter will bring equal chances of above-, below-
or near-normal temperatures, according to NOAA
forecasters. The agency today released its official winter outlook, which,
unlike most of the last six winters, is not expected to be influenced
by a strong El
Niño or La
Niña. Though weak El Niño conditions are possible by
the end of November, NOAA forecasters expect a minimal impact on the United
States. (Click NOAA image for larger view of forecast winter temperatures
for the USA. Click here
for high resolution version, which is a large file. Please credit “NOAA.)

The forecast
also projected the multi-year drought in the West will likely continue
with limited improvement and lingering water shortages. The winter outlook
will be updated on Nov. 20.

Reasons
for Uncertainty
“Without a strong El Niño or La Niña signal as a guide,
there is more uncertainty in our forecast, but we do expect winter to
bring its typical weather variability,” said John Jones, Jr., deputy
director of the NOAA National Weather Service. (Click NOAA image
for larger view of forecast winter precipitation for the USA. Click
here for high resolution version, which is a large file. Please credit
“NOAA.)

He added
that forecasters, in cases where a dominant climate feature in the Pacific
Ocean is missing, rely on historical trends of temperature and precipitation
averages as well as dynamical and statistical models.

Jones
said researchers are studying other climatic factors that influence NOAA’s
seasonal outlooks, but these influences aren’t yet routinely predictable
on seasonal time scales. As examples, he cited several factors that need
further study and pose significant challenges to the climate forecast,
including: tropical ocean temperatures in the western Pacific and Indian
Oceans, atmospheric circulation patterns in the Arctic and North Atlantic,
snow cover in the high latitudes during the late fall and U.S. soil moisture
conditions. (Click NOAA image for larger view of drought outlook
for the USA. Click here
for high resolution version, which is a large file. Please credit “NOAA.)

“There
is a need to continue collaborating with the research community for improving
data management and collection operations, and fine-tuning the oceanic
and atmospheric models that run on the supercomputers,” Jones said.
“Forecast uncertainty in low climate signal years like this can
be reduced, but it will take more research and more resources to do that."

Jones said
the conditions this year also highlight the value of collecting and sharing
data on a global scale. NOAA is moving aggressively on that front with
action that came out of the Administration-sponsored Earth Observation
Summit that was held this summer in Washington, D.C. At that session,
more than 34 nations plus the European Commission launched the development
of a 10-year implementation plan to arrange a system of integrated space-borne,
airborne and in situ observations to help understand and address global
environmental and economic concerns. NOAA, NASA and the U.S. State Department
hosted the summit.

Winter
2003-04 Outlook
“While ocean temperatures in the tropical Pacific are warmer than
long-term averages, and may even reach the level of a weak El Niño
by late November, El Niño is not expected to exert a major influence
on U.S. climate this winter,” said Ed O’Lenic, senior meteorologist
and lead forecaster at the NOAA
Climate Prediction Center, which is part of the NOAA
National Weather Service. “Our forecast tools imply large uncertainty
in the northern and eastern U.S., while a clearer picture emerges elsewhere.”

Based on
those tools, NOAA forecasters expect:

In Alaska,
the far West, the Southwest, and the southern Plains, temperatures will
likely be warmer than the long-term averages;

Elsewhere,
there are equal chances of above, below and normal temperatures;

The majority
of the nation will have equal chances of above, below and normal precipitation,
with the exception of Texas, Oklahoma and areas of western Louisiana,
southwestern Arkansas and eastern New Mexico, where above normal amounts
are likely.

NOAA forecasters
also expect existing multi-year drought conditions in much of the West
(except California) and parts of the Central Plains to continue with improvement
in complex patterns predominantly in the north central plains and parts
of the far west. In most other areas drought will likely persist—or
improve—with many lingering, long-term water shortages.

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